The present application relates to a microchip and a method of producing the microchips. More particularly, the present application relates to a microchip used for chemically or biologically analyzing a substance which is introduced into regions arranged on a substrate of the microchip.
Recently, microchips in which wells or flow passages are provided, which are used for performing a chemical or biological analysis on a silicon or glass substrate, have been developed, applying fine processing technologies in semiconductor industries (See, for example, Patent Literature 1). These microchips are beginning to be utilized in, for example, electrochemical detectors of liquid chromatography, and compact size electrochemical sensors in medical fields.
An analysis system using such microchips is called a micro-Total-Analysis System (μ-TAS), lab-on-chip or bio-chip, which receives attention as a technique enabling chemical and biological analyses to speed up, further improve in efficiency or integration, or analyzers to minimize.
The μ-TAS is expected to be applied to biological analysis handling particularly valuable, microvolume samples or a lot of specimens, because it can analyze a sample even in a small amount, or microchips used therein can be disposable.
As an application utilizing the μ-TAS, there are optical detectors in which a substance is introduced into multiple regions arranged on a microchip, and the substance is optically detected. Examples of the optical detector may include an electrophoresis apparatus in which multiple substances are separated in a flow passage on a microchip by electrophoresis and each substance separated is optically detected, and a reaction apparatus (for example a real-time PCR apparatus) in which multiple substances are reacted in wells on a microchip and the resulting substances are optically detected.
In the μ-TAS, because a sample is used in a trace amount, it is difficult to introduce the sample solution into wells or a flow passage, the introduction of the sample solution may be inhibited due to air existing within the wells and the like, and it may take a long time to introduce the sample. In addition, when a sample solution is introduced, air voids may be generated within wells and the like. Consequently, the amounts of the sample solution introduced into the wells vary, thus resulting in a lowering of the precision or efficiency of analysis. When a sample is heated, as in PCR, air voids remaining in wells expand, which inhibits the reaction or decreases the precision of analysis.
In order to easily introduce the sample solution in the μ-TAS, for example, Patent Literature 2 discloses a “substrate including at least a sample-introducing part for introducing the samples, a plurality of storing parts for storing the samples, and a plurality of air-discharging parts connected to the storing parts, in which two or more of the air-discharging parts are communicated with one open channel having one opened terminal.” In this substrate, the air-discharging part is connected to each of the storing parts, and therefore when the sample solution is introduced from the sample-introducing part to the storing parts, the air existing in the storing parts is discharged from the air-discharging parts, with the result that the sample solution can smoothly be filled into the storing parts.